Standard Cell Potentials Eθcell Values and Electrochemical Cells

The cell reaction is the overall chemical reaction that happens in both half cells. Oxidation takes place in one half cell and reduction takes place in the other. Each half cell has a standard electrode potential. The standard cell potential is the potential difference between the two half cells. A silver-copper cell is made by connecting together two half cells.Cu²⁺(aq) + 2 e^- ⇌ Cu(s) E^θ = +0.34 VAg⁺(aq) + e^- ⇌ Ag(s) E^θ = +0.80 VAg⁺ ions have a greater tendency to accept electrons than Cu²⁺ ions so the E^θ is more positive. The Ag⁺ ion is the stronger oxidising agent. Therefore it removes electrons from copper Cu(s) the strongest reducing agent. Ag⁺ is reducedAg⁺(aq) + e^- ⇌ Ag(s) E^θ=+0.80VCu(s) is oxidisedCu(s) ⇌ Cu²⁺(aq) + 2 e^- E^θ=+0.34VThe overall equation is obtained by balancing the electrons so they cancel out and adding the two half equations. The standard cell potential is the more positive minus the more negative.E^θ_cell = 0.80 - 0.34 = 0.46 V